198 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 22, 



January 22, 1873. 



Charles Fox Strangways, Esq., of the Geological Survey of Eng- 

 land and "Wales, 45 East Mount Road, York ; Alexander Irving, 

 Esq., High School, Nottingham; Thomas Lidney Dickinson, Esq., 

 of Newbold, near Chesterfield; "William Bath Kemshead, M.A., 

 Ph.D., F.R.A.S., Lecturer on Chemistry and Physical Science, Dul- 

 wich College, Hanover Villa, Thurlow Park Road, Dulwich, S.E. ; 

 J. M'Murtrie, Esq, of the Radstock Collieries, Somersetshire ; and 

 John Dawes, Jun., Esq., Manor Colliery, Hales Owen, near Bir- 

 mingham, were elected Fellows of the Society. 



The following communication was read : — 



On tlie Glaciation of Ireland. 

 By J. F. Campbell, Esq., F.G.S. 



The following notes are founded chiefly upon observations made 

 while travelling about Ireland in 1863 and 1872, and at interme- 

 diate dates. 



A subject may be treated in two ways. If the whole of a story 

 is known it may be told historically, from the beginning ; but if a 

 lesson has to be learned, it is best to work back towards the un- 

 known beginning. A great deal has yet to be learned about glacia- 

 tion ; so I begin at the end. 



I. Iceland and. Ireland, in different latitudes, are about the same 

 size. In one island are ice systems, in the other none. Some Ice- 

 landic glaciers are wide as an Irish province ; and others would cover 

 Irish counties. In Ireland lakes seldom freeze, and snow melts off 

 the highest tops early in spring. But Ireland is glaciated. 



II. Ireland. — The meridian 8° west cuts Ireland nearly in half. 

 In the north it passes near Arrigle, the highest hill in Donegal ; in 

 the south it passes near Cork. But the figure of the island is not 

 square to meridians. A line drawn through Dursey Island and 

 Rathlin, S.W. and N.E. or thereby, passes through the long axis of 

 a diamond whose shorter axis runs from the Tuskar Eock in Wex- 

 ford north-westwards to near Achill Island in Mayo. The configu- 

 ration of surface within this area has relation generally to two main 

 lines, K.E. and N.W. In Donegal, Mayo, Galway, Kerry, and 

 Cork the largest mountain-ridges and hollows trend N.E. The 

 course of the Shannon, the largest river in Ireland, is from the east 

 of north. Most of the largest sea-lochs in Ireland trend N.E. and 

 S.W. Passes in the Mourne Mountains (in Down), Carlingford 

 Lough on the east coast, and the valley of the Erne on the west 

 trend N.W. and S.E. The hollows which contain the river Ban and 

 Loch jNeagh and the valley of the Waterford river trend north and 

 south. But for one great hollow running north and south a great 

 number run N.W., and a greater number N.E. It is easily seen on 

 any good map of Ireland that roads, canals, railways, rivers, lakes, 

 harbours, and marshes, which occupy hollows and avoid hills, have 



